Laws on this vary by jurisdiction. We cannot answer this accurately without knowing your location.
As many as you want, provided you're legally able to own them.
In many instances, yes.
The "better" question would be "how many murders, rapes, and robberies are prevented by home guns ?"
No. Machine guns will beat Gatling guns.
read the Second amendment. When the Constitution uses the phrase "the people" it means the individuals who are citizens.
You have to earn the golden guns
Your question assumes that people shouldn't be able to buy guns "in the market", whatever that means, which is far from proven.
About 1/3rd of American households own at least one firearm
to scare people
how many types of guns are there in the world?
because of protection in your home for your kids especially
guns are fired in less than 2% of home-intruders